implemented the ngx.req.header table interface for retrieving all the request headers for Lua. thanks moodydeath.

README.markdown

@@ -905,13 +905,34 @@ same does assigning an empty table:
 `ngx.header` is not a normal Lua table so you cannot
 iterate through it.
 
-For reading request headers, use `ngx.var.http_HEADER`, that is, nginx's standard $http_HEADER variables:
+For reading request headers, see the `ngx.req.header` interface instead.
+
+Reading values from ngx.header.HEADER is not implemented yet,
+and usually you shouldn't need it.
+
+ngx.req.header
+--------------
+* **Context:** `rewrite_by_lua*`, `access_by_lua*`, `content_by_lua*`
+
+This read-only Lua table holds all of the request headers. Because it is an ordinary Lua table,
+iterating through it via Lua's `pairs` function is supported, for instance,
+
+    local h = {}
+    for k, v in pairs(ngx.req.header) do
+        h[k] = v
+    end
+
+For performance reasons, this table
+is generated on-the-fly at the first time it is accessed.
+
+This Lua table is read-only, setting values to this table will not automatically modify the request headers on the Nginx land.
+(TODO: we'll provide `ngx.req.set_header()` and `ngx.req.clear_header()` for
+request header modification.)
+
+Another way to read individual request headers is to use `ngx.var.http_HEADER`, that is, nginx's standard $http_HEADER variables:
 
     http://wiki.nginx.org/NginxHttpCoreModule#.24http_HEADER
 
-Reading values from ngx.header.HEADER is not implemented yet, and usually you
-shouldn't need it.
-
 ngx.exec(uri, args)
 -------------------
 * **Context:** `rewrite_by_lua*`, `access_by_lua*`, `content_by_lua*`

src/ngx_http_lua_hook.c

@@ -42,6 +42,7 @@ static void log_wrapper(ngx_http_request_t *r, const char *ident, int level,
         lua_State *L);
 static uintptr_t ngx_http_lua_escape_uri(u_char *dst, u_char *src,
         size_t size, ngx_uint_t type);
+static void ngx_http_lua_create_req_header_table(lua_State *L);
 
 #if defined(NDK) && NDK
 static ndk_set_var_value_pt ngx_http_lookup_ndk_set_var_directive(u_char *name,
@@ -1933,6 +1934,88 @@ ngx_http_lua_ngx_set(lua_State *L) {
 }
 
 
+int
+ngx_http_lua_ngx_req_get(lua_State *L) {
+    u_char                      *p;
+    size_t                       len;
+
+    p = (u_char *) luaL_checklstring(L, -1, &len);
+
+    if (len == sizeof("header") - 1 &&
+            ngx_strncmp(p, "header", sizeof("header") - 1) == 0)
+    {
+        ngx_http_lua_create_req_header_table(L); /* req "header" header */
+        lua_insert(L, 2); /* req header "header" */
+        lua_pushvalue(L, 2); /* req header "header" header */
+        lua_rawset(L, 1); /* req header */
+
+        return 1;
+    }
+
+    dd("key %s not matched", p);
+
+    lua_pushnil(L);
+    return 1;
+}
+
+
+static void
+ngx_http_lua_create_req_header_table(lua_State *L) {
+    ngx_list_part_t              *part;
+    ngx_table_elt_t              *header;
+    ngx_http_request_t           *r;
+    ngx_uint_t                    i;
+
+    lua_getglobal(L, GLOBALS_SYMBOL_REQUEST);
+    r = lua_touserdata(L, -1);
+    lua_pop(L, 1);
+
+    if (r == NULL) {
+        luaL_error(L, "no request object found");
+        return;
+    }
+
+    lua_createtable(L, 0, 8); /* Firefox creates 8 headers in its requests */
+
+    part = &r->headers_in.headers.part;
+    header = part->elts;
+
+    for (i = 0; /* void */; i++) {
+
+        if (i >= part->nelts) {
+            if (part->next == NULL) {
+                break;
+            }
+
+            part = part->next;
+            header = part->elts;
+            i = 0;
+        }
+
+        lua_pushlstring(L, (char *) header[i].key.data, header[i].key.len);
+        lua_pushlstring(L, (char *) header[i].value.data, header[i].value.len);
+        lua_rawset(L, -3);
+
+        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+                       "http lua req header: \"%V: %V\"",
+                       &header[i].key, &header[i].value);
+    }
+}
+
+
+int
+ngx_http_lua_ngx_req_set(lua_State *L) {
+    u_char                      *p;
+    size_t                       len;
+
+    /* we skip the first argument that is the table */
+    p = (u_char *) luaL_checklstring(L, 2, &len);
+
+    return luaL_error(L, "Attempt to write to ngx.req. with the key \"%s\"", p);
+}
+
+
+
 int
 ngx_http_lua_header_get(lua_State *L)
 {

src/ngx_http_lua_hook.h

@@ -49,6 +49,9 @@ int ngx_http_lua_ngx_location_capture_multi(lua_State *L);
 int ngx_http_lua_ngx_get(lua_State *L);
 int ngx_http_lua_ngx_set(lua_State *L);
 
+int ngx_http_lua_ngx_req_get(lua_State *L);
+int ngx_http_lua_ngx_req_set(lua_State *L);
+
 int ngx_http_lua_header_get(lua_State *L);
 int ngx_http_lua_header_set(lua_State *L);
 

src/ngx_http_lua_util.c

@@ -631,6 +631,21 @@ init_ngx_lua_globals(lua_State *L)
 
     lua_setfield(L, -2, "var");
 
+    /* {{{ ngx.req table */
+
+    lua_newtable(L);    /* .req */
+
+    lua_createtable(L, 0, 2); /* metatable for .header */
+    lua_pushcfunction(L, ngx_http_lua_ngx_req_get);
+    lua_setfield(L, -2, "__index");
+    lua_pushcfunction(L, ngx_http_lua_ngx_req_set);
+    lua_setfield(L, -2, "__newindex");
+    lua_setmetatable(L, -2);
+
+    lua_setfield(L, -2, "req");
+
+    /* }}} */
+
 #if 1
     lua_newtable(L);    /* .header */
 

t/028-req-header.t

@@ -0,0 +1,79 @@
+# vim:set ft= ts=4 sw=4 et fdm=marker:
+
+use lib 'lib';
+use Test::Nginx::Socket;
+
+#worker_connections(1014);
+#master_process_enabled(1);
+#log_level('warn');
+
+repeat_each(2);
+#repeat_each(1);
+
+plan tests => blocks() * repeat_each() * 2;
+
+#no_diff();
+#no_long_string();
+
+run_tests();
+
+__DATA__
+
+=== TEST 1: random access req headers
+--- config
+    location /req-header {
+        content_by_lua '
+            ngx.say("Foo: ", ngx.req.header["Foo"] or "nil")
+            ngx.say("Bar: ", ngx.req.header["Bar"] or "nil")
+        ';
+    }
+--- request
+GET /req-header
+--- more_headers
+Foo: bar
+Bar: baz
+--- response_body
+Foo: bar
+Bar: baz
+
+
+
+=== TEST 2: iterating through headers
+--- config
+    location /req-header {
+        content_by_lua '
+            local h = {}
+            for k, v in pairs(ngx.req.header) do
+                h[k] = v
+            end
+            ngx.say("Foo: ", h["Foo"] or "nil")
+            ngx.say("Bar: ", h["Bar"] or "nil")
+        ';
+    }
+--- request
+GET /req-header
+--- more_headers
+Foo: bar
+Bar: baz
+--- response_body
+Foo: bar
+Bar: baz
+
+
+
+=== TEST 3: setting req header table
+--- config
+    location /req-header {
+        content_by_lua '
+            ngx.req.header.foo = 3;
+            ngx.say(ngx.req.header.foo)
+        ';
+    }
+--- request
+GET /req-header
+--- more_headers
+Foo: bar
+Bar: baz
+--- response_body
+3
+